title: Spinal neuronal NOS activation mediates sigma-1 receptor-induced mechanical and thermal hypersensitivity in mice: involvement of PKC-dependent GluN1 phosphorylation.
abstract: BACKGROUND AND PURPOSE We recently demonstrated that activation of the spinal sigma-1 receptor induces mechanical and thermal hypersensitivity via calcium-dependent second messenger cascades and phosphorylation of the spinal NMDA receptor GluN1 subunit (pGluN1). Here we examined the role of NO in this process, as it plays a critical role in PKC-mediated calcium signalling and the potentiation of NMDA receptor function. EXPERIMENTAL APPROACH The effects of intrathecal (i.t.) pretreatment with nNOS inhibitors on PRE084 (sigma-1 receptor agonist)-induced pain were assessed in mice by use of mechanical allodynia and thermal hyperalgesia tests. Western blot analysis, immunoprecipitation and immunohistochemical techniques were used to determine effects of these treatments on spinal pGluN1-immunoreactive (ir) cells, whether PRE084 induces a time-dependent modification of nNOS activity in the dorsal horn, and if any changes in nNOS activity can be blocked by sigma-1 receptor, calcineurin or soluble guanylyl cyclase (sGC) inhibitors. KEY RESULTS PRE084, injected i.t., induced mechanical and thermal hypersensitivity, and increased the number of PKC- and PKA-dependent pGluN1-ir cells in spinal cord. This PRE084-induced hypersensitivity and increase in PKC-dependent pGluN1 expression were blocked by pretreatment with N(G) -nitro-L-arginine methyl ester (L-NAME) or 7-nitroindazole (7-NI). PRE084 also time-dependently decreased the ratio of phosphorylated nNOS (pnNOS) to nNOS expression and the number of spinal pnNOS-ir cells. This decrease in pnNOS was prevented by BD1047, a sigma-1 receptor antagonist and cyclosporin A, a calcineurin inhibitor, but not by a sGC inhibitor. CONCLUSIONS AND IMPLICATIONS Spinal sigma-1 receptor-induced sensitization is mediated by an increase in nNOS activity, which is associated with an NO-induced increase in PKC-dependent pGluN1 expression.
authors.affiliation: Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Roh
authors.forename: Sheu-Ran
authors.initials: SR
authors.lastname: Choi
authors.forename: Seo-Yeon
authors.initials: SY
authors.lastname: Yoon
authors.forename: Suk-Yun
authors.initials: SY
authors.lastname: Kang
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Moon
authors.forename: Soon-Gu
authors.initials: SG
authors.lastname: Kwon
authors.forename: Ho-Jae
authors.initials: HJ
authors.lastname: Han
authors.forename: Alvin J
authors.initials: AJ
authors.lastname: Beitz
authors.forename: Jang-Hern
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D035061:Control Groups; D000076122:Disks Large Homolog 4 Protein; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D051528:Guanylate Kinases / Q000032:analysis / Q000096:biosynthesis; D006930:Hyperalgesia / Q000378:metabolism* / Q000517:prevention & control; D007278:Injections, Spinal; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis; D051379:Mice; D008813:Mice, Inbred ICR; D009025:Morpholines / Q000008:administration & dosage / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage / Q000494:pharmacology; D052248:Nitric Oxide Synthase Type I / Q000032:analysis / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D017480:Receptors, sigma / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D000097605:Sigma-1 Receptor
chemical_list: D000701:Analgesics, Opioid; D000076122:Disks Large Homolog 4 Protein; D004791:Enzyme Inhibitors; D051528:Guanylate Kinases; D008565:Membrane Proteins; D009025:Morpholines; D019331:NG-Nitroarginine Methyl Ester; D052248:Nitric Oxide Synthase Type I; D011493:Protein Kinase C; D016194:Receptors, N-Methyl-D-Aspartate; D017480:Receptors, sigma; D000097605:Sigma-1 Receptor; C501447:Dlg4 protein, mouse; C071738:2-(4-morpholino)ethyl-1-phenylcyclohexane-1-carboxylate; C496320:NOS1 protein, human